[3/3] AudioFX: Add center frequency param to bassboost

Change-Id: I49da8e5ab24502d0de5c09b7fc9f4b8a51bead60
(cherry picked from commit 0b8cc28664215dd7079f28711f7853bbe382d05d)
[3/3] AudioEffect: Add a stereo widener effect

Change-Id: Iab2035c5601394b060e7e77e85ad85aca6e4c89f
(cherry picked from commit 0681b632dc5f786157812e526b7cf692bbc83528)